Dielectric　elastomers　(DEs)　are　one　of　the　optimal　artificial　muscle　candidates　and　featured　for　their　light　weight,　fast　response,　and　large　stroke.　However,　high　operating　voltage　and　prestrain　processing　are　hindering　their　practical　applications.　In　this　work,　a　remarkable　dielectric　elastomer,　vinyl　chloride　and　ethylene　copolymer　(P(VC-E)),　is　developed　by　a　novel　strategy　of　main　chain　dipole　manipulation,　which　tackles　the　contradiction　between　the　large　permittivity,　low　modulus,　and　high　breakdown　strength.　The　synthesis　of　polymer　is　conducted　by　a　controlled　reduction　of　poly(vinyl　chloride),　and　the　chemical　composition　and　glass　transition　temperature　of　resultant　DE　can　be　simply　tuned　by　varying　the　reductant　dosage.　It　is　found　that　P(VC-E)　bearing　40　mol%　vinyl　chloride　exhibits　the　highest　breakdown　strength　(85　MV　m−1)　among　high-k　(＞10)　DEs,　and　much　larger　strain　(38%　in　the　thickness)　at　1　kV　than　DEs　without　prestrain.　Moreover,　the　actuator　fabricated　from　P(VC-E)　demonstrates　superior　cyclical　operability　under　a　relatively　low　voltage　(450　V)　and　an　extremely　long　lifetime.　The　facile　material　preparation　and　device　fabrication　present　the　significant　potential　of　material　scaled-up　and　device　production　at　a　low　cost,　providing　a　new　pathway　for　DEs　in　flexible　actuator　applications.　©　2022　Elsevier　B.V.